Fetal exposure to certain phthalate esters can disrupt testis development in rodents and lead to male reproductive disorders, but with a causal link less certain in humans. Di(2-ethylhexyl) phthalate (DEHP) is one of the most common phthalates found in the environment and in rodents it is known to induce serious testis toxicity, as well as male reproductive disorders including cryptorchidism, hypospadias, impaired spermatogenesis and reduced fertility. In this study, we show that perinatal DEHP exposure disrupts gap junction localization in fetal and postnatal rat testis and correlate these findings to morphological changes. The protein Connexin 43 (CX43), normally expressed strongly in testicular gap junctions, was markedly downregulated in Leydig cells of DEHP-exposed fetal testes. In the postnatal testes, CX43 expression was recovered in the DEHP-exposed animals, even though Leydig cell clusters and malformed cords with intratubular Leydig cells were still present.

The modulation of energetic homeostasis by pollutants has recently emerged as a potential contributor to the onset of metabolic disorders. Diethylhexyl phthalate (DEHP) is a widely used industrial plasticizer to which humans are widely exposed. Phthalates can activate the three peroxisome proliferator-activated receptor (PPAR) isotypes on cellular models and induce peroxisome proliferation in rodents.

Exposure to environmental chemicals during windows of development is a potentially contributing factor in gut microbiota dysbiosis and linked to chronic diseases and developmental disorders. We used a community-level model of microbiota metabolism to investigate the effects of diethylhexyl phthalate (DEHP), a ubiquitous plasticizer implicated in neurodevelopmental disorders, on the composition and metabolite outputs of gut microbiota in young mice. Administration of DEHP by oral gavage increased the abundance of Lachnoclostridium, while decreasing Clostridium sensu stricto Addition of DEHP to in vitro-cultured cecal microbiota increased the abundance of Paenibacillus and Lachnoclostridium Untargeted metabolomics showed that DEHP broadly altered the metabolite profile in the culture. Notably, DEHP enhanced the production of p-cresol while inhibiting butyrate synthesis. Metabolic model-guided correlation analysis indicated that the likely sources of p-cresol are Clostridium species. Monoculture of Lachnoclostridium bolteae confirmed that it is capable of producing p-hydroxyphenylacetic acid, the immediate precursor of p-cresol, and that the species' growth is enhanced upon DEHP exposure. Taken together, these findings suggest a model where DEHP increases production of p-cresol, a bacterial metabolite linked with neurodevelopmental disorders, by expanding the abundance of species that synthesize the metabolite's precursor.IMPORTANCE Several previous studies have pointed to environmental chemical exposure during windows of development as a contributing factor in neurodevelopmental disorders and correlated these disorders with microbiota dysbiosis; however, little is known about how the chemicals specifically alter the microbiota to interfere with development. The findings reported in this paper unambiguously establish that a pollutant linked with neurodevelopmental disorders can directly modify the microbiota to promote the production of a potentially toxic metabolite (p-cresol) that has also been correlated with neurodevelopmental disorders. Furthermore, we used a novel modeling strategy to identify the responsible enzymes and bacterial sources of this metabolite. To the best of our knowledge, the present study is the first to characterize the functional consequence of phthalate exposure on a developed microbiota. Our results suggest that specific bacterial pathways could be developed as diagnostic and therapeutic targets against health risks posed by ingestion of environmental chemicals.

Phthalates may disturb metabolic homeostasis in the liver by interfering with the peroxisome proliferator-activated receptors (PPARs). However, the role of hepatic macrophages in the lipid metabolic dysregulation induced by diethylhexyl phthalate (DEHP) remains unclear.

Diethylhexyl phthalate (DEHP) is one of the most widely utilized phthalate plasticizers. Previous studies have demonstrated that gestational or postnatal DEHP exposure induced adverse effects on rat brain development and function. In this study, we investigated the effects of gestational DEHP exposure on gene expression profiling in neonatal rat brain and cognitive function change at adulthood. Adult Sprague Dawley dams were orally treated with 10 or 750 mg/kg DEHP from gestational day 12 to 21. Some male pups were euthanized at postnatal day 1 for gene expression profiling, and the rest males were retained for water maze testing on postnatal day (PND) 56. DEHP showed dose-dependent impairment of learning and spatial memory from PND 56 to 63. Genome-wide microarray analysis showed that 10 and 750 mg/kg DEHP altered the gene expression in the neonatal rat brain. Ccnd1 and Cdc2, two critical genes for neuron proliferation, were significantly down-regulated by DEHP. Interestingly, 750 mg/kg DEHP significantly increased Pmch level. Our study demonstrated the changed gene expression patterns after in utero DEHP exposure might partially contribute to the deficit of cognitive function at adulthood.

Phthalate exposure through skin is often neglected due to the small quantity and limited dermal absorption rate. However, free phthalate can be ingested by hand-to-mouth action or by contact with food. To evaluate the effectiveness in removing phthalate exposure on hand, we compare here the removal efficiency of di-(2-ethylhexyl)phthalate (DEHP) on hands by handwashing with soap-and-water versus water-only. In two three-day N-of-1 trials, residual DEHP was measured in a single female adult who washed exposed hands with soap-and-water or water-only. Subsequently, a crossover study was performed by randomly assigning another 28 subjects equally to wash with soap-and-water or with water-only, and then each one received the other treatment 24 hrs later. In the N-of-1 trials, mean DEHP removal rates range from 95.9% (SD = 0.1%) to 97.0% (SD = 2.5%) for soap-and-water handwashes, and 1.8% (SD = 0.1%) to 7.0% (SD = 0.3%) (n = 3) for water-only. In the crossover study, mean removal rate was 94.6% (SD = 6.5%) for handwashing with soap-and-water (n = 28) and 8.7% (SD = 5.7%) for water-only (n = 28). We concluded that handwashing with soap-and-water removes 80% more DEHP than handwashing with water alone, and may be a cost-effective way of removing other endocrine disruptors from hands.

Several studies have suggested potential links of phthalates to obesity in children and adults. Limited evidence, however, has been available for the relations between diethylhexyl phthalate (DEHP) and obesity-related markers or body mass change in early life.

Endocrine-disrupting compounds can interfere with the endocrine organs or hormone system and cause tumors, birth defects and developmental disorders in humans. The estrogen-like activity of compounds has been widely studied but little is known concerning their possible modulation of the glucocorticoid receptor. Steroidal (synthetic and natural) and non-steroidal endocrine-active compounds commonly occur as complex mixtures in human environments. Identification of such molecular species, which are responsible for modulating the glucocorticoid receptor are necessary to fully assess their risk. We have used the MDA-kb2 cell line, which expresses endogenous glucocorticoid receptor and a stably transfected luciferase reporter gene construct, to quantify the glucocorticoid-like activity of four compounds present in products in everyday use - propylparaben (PP), butylparaben (BP), diethylhexyl phthalate (DEHP) and tetramethrin (TM). We tested all possible combinations of these compounds at two concentrations (1 μM and 10 nM) and compared their glucocorticoid-like activity. At the concentration of 1 μM seven mixtures were identified to have glucocorticoid-like activity except: DEHP+TM, BP+TM, DEHP+PP+TM, BP+PP+TM. At the concentration of 10 nM only three mixtures have glucocorticoid modulatory activity: DEHP+PP, BP+PP, DEHP+BP+PP+TM. Identified glucocorticoid-like activities were between 1.25 and 1.51 fold at the concentration of 1 μM and between 1.23 and 1.44 fold at the concentration of 10 nM in comparison with the solvent control. Individually BP, PP, and DEHP had glucocorticoid-like activity of 1.60, 1.57 and 1.50 fold over the solvent control at the concentration of 1 μM. On the other hand PP and DEHP, at the concentration of 10nM, showed no glucocorticoid-like activity, while BP showed 1.44 fold. The assertion that individual glucocorticoid-like compounds do not produce harm because they are present at low, ineffective levels in humans may be irrelevant when we include mixed exposures. This study emphasizes that risk assessment of compounds should take mixture effects into account.

Diethylhexyl phthalate (DEHP) is used in many plastic products, such as perfumes, lunch boxes, bags, and building materials. As DEHP is not covalently bound to the plastic, humans can be easily exposed to it. DEHP induces neurobehavioral changes and neuronal cell death; however, the exact mechanism behind this is still unclear. We hypothesized that the neurotoxic mechanism is related to DEHP-induced oxidative stress leading to apoptosis through mitochondrial fission. We demonstrated that DEHP-induced oxidative stress triggers neuronal cell death via mitochondrial fission in mouse hippocampal HT-22 cells. Furthermore, we identified that peroxiredoxin 5 (Prx5), an antioxidant enzyme induced by DEHP, prevents DEHP-induced mitochondrial fission by inhibiting the production of reactive oxygen species. We conclude that Prx5 may be a promising therapeutic target for mitigating DEHP-induced neuronal cell death.

Emission rates of diethylhexyl phthalate (DEHP) from building materials, such as vinyl floorings and wall paper, determined using a passive flux sampler (PFS) were constant over the week-long measurement period. Emission rates for vinyl floorings and wallpaper were linearly correlated to the inverse of diffusion distance, which corresponds to the internal depth of the PFS. Surface-air DEHP concentrations (y0) were estimated as 1.3-2.3 μg/m3 for materials having a boundary layer molecular diffusion rate-limiting step. The partition coefficient (Kmaterial-air) was estimated as 3.3-7.5 × 1010 for these materials. Additionally, emission rates of DEHP from same building materials determined using a micro-chamber were 4.5-6.1 μg/m2/h. Mass transfer coefficients in the micro-chamber (hm) were estimated by comparing the results using the PFS and micro-chamber, and these were 1.1-1.2 × 10-3 and 8.1 × 10-4 m/s for vinyl floorings (smooth surface) and wallpaper (rough surface), respectively. The thickness of boundary layer on the surface of building materials in the micro-chamber were estimated to be 2.5-2.6 and 3.7 mm for vinyl floorings and wallpaper, respectively.

A temporal decline in human and dog sperm quality is thought to reflect a common environmental aetiology. This may reflect direct effects of seminal chemicals on sperm function and quality. Here we report the effects of diethylhexyl phthalate (DEHP) and polychlorinated biphenyl 153 (PCB153) on DNA fragmentation and motility in human and dog sperm. Human and dog semen was collected from registered donors (n = 9) and from stud dogs (n = 11) and incubated with PCB153 and DEHP, independently and combined, at 0x, 2x, 10x and 100x dog testis concentrations. A total of 16 treatments reflected a 4 × 4 factorial experimental design. Although exposure to DEHP and/or PCB153 alone increased DNA fragmentation and decreased motility, the scale of dose-related effects varied with the presence and relative concentrations of each chemical (DEHP.PCB interaction for: DNA fragmentation; human p < 0.001, dog p < 0.001; Motility; human p < 0.001, dog p < 0.05). In both human and dog sperm, progressive motility negatively correlated with DNA fragmentation regardless of chemical presence (Human: P < 0.0001, r = -0.36; dog P < 0.0001, r = -0.29). We conclude that DEHP and PCB153, at known tissue concentrations, induce similar effects on human and dog sperm supporting the contention of the dog as a sentinel species for human exposure.

Background: Prenatal exposures to endocrine disrupting chemicals (EDCs) are correlated with adverse behavioral outcomes, but the effects of combinations of these chemicals are unclear. The aim of this study was to determine the dose-dependent effects of prenatal exposure to EDCs on male and female behavior. Methods: Pregnant Sprague-Dawley rats were orally dosed with vehicle, bisphenol A (BPA) (5 μg/kg body weight (BW)/day), low-dose (LD) diethylhexyl phthalate (DEHP) (5 μg/kg BW/day), high-dose (HD) DEHP (7.5 mg/kg BW/day), a combination of BPA and LD-DEHP (B + D (LD)), or a combination of BPA and HD-DEHP (B + D (HD)) on gestational days 6-21. Adult offspring were subjected to the Open Field Test (OFT), Elevated Plus Maze (EPM), and Shock Probe Defensive Burying test (SPDB) in adulthood. Body, adrenal gland, and pituitary gland weights were collected at sacrifice. Corticosterone (CORT) was measured in the serum. Results: Female EDC-exposed offspring showed anxiolytic effects in the OFT, while male offspring were unaffected. DEHP (HD) male offspring demonstrated a feminization of behavior in the EPM. Most EDC-exposed male offspring buried less in the SPDB, while their female counterparts showed reduced shock reactivity, indicating sex-specific maladaptive alterations in defensive behaviors. Additionally, DEHP (LD) males and females and B + D (LD) females displayed increased immobility in this test. DEHP (LD) alone and in combination with BPA led to lower adrenal gland weights, but only in male offspring. Finally, females treated with a mixture of B + D (HD) had elevated CORT levels. Conclusion: Prenatal exposure to BPA, DEHP, or a mixture of the two, affects behavior, CORT levels, and adrenal gland weights in a sex- and dose-dependent manner.

Exposure to diethylhexyl phthalate (DEHP), the most abundant plasticizer used in the production of polyvinyl-containing plastics, has been associated to adverse reproductive health outcomes in both males and females. While the effects of DEHP on reproductive health have been widely investigated, the molecular mechanisms by which exposure to environmentally-relevant levels of DEHP and its metabolites impact the female germline in the context of a multicellular organism have remained elusive. Using the Caenorhabditis elegans germline as a model for studying reprotoxicity, we show that exposure to environmentally-relevant levels of DEHP and its metabolites results in increased meiotic double-strand breaks (DSBs), altered DSB repair progression, activation of p53/CEP-1-dependent germ cell apoptosis, defects in chromosome remodeling at late prophase I, aberrant chromosome morphology in diakinesis oocytes, increased chromosome non-disjunction and defects during early embryogenesis. Exposure to DEHP results in a subset of nuclei held in a DSB permissive state in mid to late pachytene that exhibit defects in crossover (CO) designation/formation. In addition, these nuclei show reduced Polo-like kinase-1/2 (PLK-1/2)-dependent phosphorylation of SYP-4, a synaptonemal complex (SC) protein. Moreover, DEHP exposure leads to germline-specific change in the expression of prmt-5, which encodes for an arginine methyltransferase, and both increased SC length and altered CO designation levels on the X chromosome. Taken together, our data suggest a model by which impairment of a PLK-1/2-dependent negative feedback loop set in place to shut down meiotic DSBs, together with alterations in chromosome structure, contribute to the formation of an excess number of DSBs and altered CO designation levels, leading to genomic instability.

The etiology of autism spectrum (ASD) and Attention Deficit/Hyperactivity (ADHD) disorders are multifactorial. Epidemiological studies have shown associations with environmental pollutants, such as plasticizers. This study focused on two of these compounds, the Bisphenol-A (BPA) and Diethylhexyl Phthalate (DEHP). The major pathway for BPA and DEHP excretion is via glucuronidation. Glucuronidation makes insoluble substances more water-soluble allowing for their subsequent elimination in urine.

In 2011, the Taiwan Food and Drug Administration inadvertently discovered that, for decades, manufacturers had replaced expensive natural emulsifiers in food products with diethylhexyl phthalate (DEHP). We wanted to compare urinary phthalate metabolite levels of children before and after the DEHP food contamination event and identify source(s) of phthalate exposure in addition to the illegal food additives. In the present study, morning urine samples were collected from a cohort of 453 children in 2010 in Taipei. After the DEHP food contamination event, there were 200 cohort children left at follow-up in 2013. The geometric means (GMs) of urinary mono(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP) levels before and after the event were 9.39 and 13.34 µg/g of creatinine, respectively, with no significant difference (p = 0.093). After the DEHP food contamination event, we found that urinary phthalate metabolite levels were significantly higher in people who frequently consumed microwave-heated food and used fragrance-containing products (p < 0.05). In addition, children who did not frequently wash hands before eating had significantly higher urinary phthalate metabolite levels than those who did (p < 0.05). These results demonstrate that urinary phthalate metabolite levels did not decrease after the DEHP food contamination event, thus, other sources must contribute to phthalate exposure in daily life. Public awareness of approaches to reducing phthalate exposure is necessary.

Phthalate plasticizers are ubiquitous chemicals linked to several cardiovascular diseases in animal models and humans. Despite this, the mechanisms by which phthalate exposures cause adverse cardiac health outcomes are unclear. In particular, whether phthalate exposures during pregnancy interfere with normal developmental programming of the cardiovascular system, and the resulting implications this may have for long-term disease risk, are unknown. Recent studies suggest that the effects of phthalates on metabolic and neurobehavioral outcomes are sex-specific. However, the influence of sex on cardiac susceptibility to phthalate exposures has not been investigated. One mechanism by which developmental exposures may influence long-term health is through altered programming of DNA methylation. In this work, we utilized an established mouse model of human-relevant perinatal exposure and enhanced reduced representation bisulfite sequencing to investigate the long-term effects of diethylhexyl phthalate (DEHP) exposure on DNA methylation in the hearts of adult male and female offspring at 5 months of age (n = 5-7 mice per sex and exposure). Perinatal DEHP exposure led to hundreds of sex-specific, differentially methylated cytosines (DMCs) and differentially methylated regions (DMRs) in the heart. Pathway analysis of DMCs revealed enrichment for several pathways in females, including insulin signaling, regulation of histone methylation, and tyrosine phosphatase activity. In males, DMCs were enriched for glucose transport, energy generation, and developmental programs. Notably, many sex-specific genes differentially methylated with DEHP exposure in our mouse model were also differentially methylated in published data of heart tissues collected from human heart failure patients. Together, these data highlight the potential role for DNA methylation in DEHP-induced cardiac effects and emphasize the importance of sex as a biological variable in environmental health studies.

Developmental exposures to phthalates are suspected to contribute to risk of metabolic syndrome. However, findings from human studies are inconsistent, and long-term metabolic impacts of early-life phthalate and phthalate mixture exposures are not fully understood. Furthermore, most animal studies investigating metabolic impacts of developmental phthalate exposures have focused on diethylhexyl phthalate (DEHP), whereas newer phthalates, such as diisononyl phthalate (DINP), are understudied. We used a longitudinal mouse model to evaluate long-term metabolic impacts of perinatal exposures to three individual phthalates, DEHP, DINP, and dibutyl phthalate (DBP), as well as two mixtures (DEHP+DINP and DEHP+DINP+DBP). Phthalates were administered to pregnant and lactating females through phytoestrogen-free chow at the following exposure levels: 25 mg of DEHP/kg of chow, 25 mg of DBP/kg of chow, and 75 mg of DINP/kg of chow. One male and female per litter (n = 9 to 13 per sex per group) were weaned onto control chow and followed until 10 months of age. They underwent metabolic phenotyping at 2 and 8 months, and adipokines were measured in plasma collected at 10 months. Longitudinally, females perinatally exposed to DEHP only had increased body fat percentage and decreased lean mass percentage, whereas females perinatally exposed to DINP only had impaired glucose tolerance. Perinatal phthalate exposures also modified the relationship between body fat percentage and plasma adipokine levels at 10 months in females. Phthalate-exposed males did not exhibit statistically significant differences in the measured longitudinal metabolic outcomes. Surprisingly, perinatal phthalate mixture exposures were statistically significantly associated with few metabolic effects and were not associated with larger effects than single exposures, revealing complexities in metabolic effects of developmental phthalate mixture exposures.

Diethylhexyl phthalate (DEHP) is widely used as a plasticizer in polyvinyl chloride products. DEHP exposure, which is widespread in the US, increases preterm birth risk; however, the mechanisms driving this relationship are unclear. Because cyclooxygenase-2 (COX-2) dependent prostaglandin synthesis is implicated in preterm birth, we evaluated effects of mono-2-ethylhexyl phthalate (MEHP), the active metabolite of DEHP, on prostaglandin E2 (PGE2) synthesis and COX expression in human placental macrophages (PM). In addition, responses in PM were compared to those in a human macrophage-like cell line, THP-1.

Phthalates have been used in a wide variety of consumer goods. Their versatility as plasticizers has translated into worldwide use in a vast array of consumer products. These compounds can leach into matrices, such as food and liquids that can be routed for human exposure. One of the most used phthalates is Diethylhexyl phthalate (DEHP). Diethylhexyl phthalate and its metabolite 2-ethyl-1-hexanol (2-EH) have demonstrated biological effects which merit further evaluation. In this work, we expand on our previous work with DEHP and screen the 2-EH metabolite for different cell death endpoints such as growth inhibition, apoptosis, autophagy, caspase activation, DNA fragmentation, and cell cycle arrest using fluorophores and the NC3000 instrument. Significant results (p < 0.05) revealed higher toxicity for the 2-EH metabolite when compared to DEHP. Also, 2-EH presented apoptosis induction with characteristic hallmarks, such as loss of mitochondrial membrane potential, caspase activation, DNA fragmentation and cell cycle arrest at the S phase. In addition, the presence of autophagosome was detected through L3CB protein staining. We conclude that 2-EH presents differences in cell death endpoints that interestingly differ from the DEHP parent compound. Further studies are needed to establish the molecular pathways responsible for the observed effects.

Phthalates have been demonstrated to interfere with metabolism, presumably by interacting with peroxisome proliferator-activated receptors (PPARs). However, mechanisms linking developmental phthalate exposures to long-term metabolic effects have not yet been elucidated. We investigated the hypothesis that developmental phthalate exposure has long-lasting impacts on PPAR target gene expression and DNA methylation to influence hepatic metabolic profiles across the life course. We utilized an established longitudinal mouse model of perinatal exposures to diethylhexyl phthalate and diisononyl phthalate, and a mixture of diethylhexyl phthalate+diisononyl phthalate. Exposure was through the diet and spanned from 2 weeks before mating until weaning at postnatal day 21 (PND21). Liver tissue was analyzed from the offspring of exposed and control mice at PND21 and in another cohort of exposed and control mice at 10 months of age. RNA-seq and pathway enrichment analyses indicated that acetyl-CoA metabolic processes were altered in diisononyl phthalate-exposed female livers at both PND21 and 10 months (FDR = 0.0018). Within the pathway, all 13 significant genes were potential PPAR target genes. Promoter DNA methylation was altered at three candidate genes, but persistent effects were only observed for Fasn. Targeted metabolomics indicated that phthalate-exposed females had decreased acetyl-CoA at PND21 and increased acetyl-CoA and acylcarnitines at 10 months. Together, our data suggested that perinatal phthalate exposures were associated with short- and long-term activation of PPAR target genes, which manifested as increased fatty acid production in early postnatal life and increased fatty acid oxidation in adulthood. This presents a novel molecular pathway linking developmental phthalate exposures and metabolic health outcomes.